Despite the advancements in technologies, wireless communication technologies using the millimeter wave (also referred to as mmWave) are still facing certain technical difficulties. Basically, the first problem that use of the millimeter wave may encounter is severe attenuation of wave energy during transmission, which is highly related to millimeter wave communication systems operated in high frequency bands while using a sizable bandwidth for communication. More specifically, the millimeter wave communication systems use the frequency band with relatively high frequency for communication as compared to the third generation (3G) or the fourth generation (4G) communication systems which are commonly used nowadays, and it is well know that the propagation is poorer at higher frequencies (e.g. millimeter wave) than lower frequencies (e.g. micro wave). Energy intensity of an electromagnetic wave signal received by a receiver is inversely proportional to a square of a signal transmitting distance and is proportional to a wavelength of the electromagnetic wave signal, such that the attenuation degree of the signal energy will be significantly increased if the millimeter wave communication systems use the high frequency signal with short wavelength. That is, path loss in the millimeter wave communication systems is severe. Also, the high frequency signal will also cause sudden reduction in the antenna aperture, which may result in decrement of the signal energy of the transmitting signal in the millimeter wave communication systems.
Further, because of the electromagnetic wave signal operated in high frequency band, the capability of the transmitting/receiving signals in the millimeter wave communication systems for penetrating obstacles is significantly reduced. Generally, with respect to the millimeter wave communication systems, a system performance thereof is very sensitive to the obstacles on the signal transmission path. That is, consideration regarding whether the signal transmission takes place in the Line of Sight (LOS) and the Non Line of Sight (NLOS) environment becomes very important. Moreover, the energy of the millimeter wave may also be absorbed by, for example, rainy days, oxygen and water steam in the air, and the like. In addition, in order to accomplish high data transmission efficiency, the millimeter wave communications use the sizable bandwidth (e.g., 500 MHz to 1 GHz) for the data transmission, which will significantly increase the noise energy and accordingly reduce the signal-to-noise ratio. Therefore, in order to ensure the communication quality, a transceiver in the millimeter wave systems usually requires use of a multiple antenna beamforming technology to reduce the attenuation of the signal energy, so as to improve the efficiency for gaining the transceiving signals.
Generally, in related art, an antenna array including multiple antennas is disposed on a base station/a user equipment, so that beams with directivity may be generated by the base station/the user equipment by controlling the antennas. The beamforming technologies accomplished by the antenna array is one of the key factors for influencing performance of a millimeter wave wireless communication system. More specifically, because the beams generated by the base station/the user equipment have adjustable beam direction and beam pattern, the beam direction and the beam pattern of the beams can directly influence whether a data transmission path can be established between the base station and the user equipment. For example, the base station can establish the data transmission path with the user equipment through a beam scan, and the beam scan is performed by the base station for the beams with limited coverage which are sequentially sent towards different directions within cellular cells. Therefore, filed of view (FoV) of the beam also become one of the important factors for determining a time required in establishment of the data transmission path between the base station and the user equipment. Accordingly, it has become one of important issues to be solved for persons skilled in the art as how to improve performance of the millimeter wave wireless communication system by using the beamforming method technologies.